Assessing the real-time activation of the cannabinoid CB1 receptor and the associated structural changes using a FRET biosensor

Liu, Y. et al. (2018) Assessing the real-time activation of the cannabinoid CB1 receptor and the associated structural changes using a FRET biosensor. International Journal of Biochemistry and Cell Biology, 99, pp. 114-124. (doi: 10.1016/j.biocel.2018.04.003) (PMID:29626639)

Full text not currently available from Enlighten.

Abstract

The cannabinoid receptor 1 (CB1) is mainly expressed in the nervous system and regulates learning, memory processes, pain and energy metabolism. However, there is no way to directly measure its activation. In this study, we constructed a CB1 intramolecular fluorescence resonance energy transfer (FRET) sensor, which could measure CB1 activation by monitoring structural changes between the third intracellular loop and the C-terminal tail. CB1 agonists induced a time- and concentration-dependent increase in the FRET signal, corresponding to a reduction in the distance between the third intracellular loop and the C-terminal tail. This, in turn, mobilized intracellular Ca , inhibited cAMP accumulation, and increased phosphorylation of the ERK1/2 MAP kinases. The activation kinetics detected using this method were consistent with those from previous reports. Moreover, the increased FRET signal was markedly inhibited by the CB1 antagonist rimonabant, which also reduced phosphorylation of the ERK1/2 MAP kinases. We mutated a single cysteine residue in the sensor (at position 257 or 264) to alanine. Both mutation reduced the agonist-induced increase in FRET signal and structural changes in the CB1 receptor, which attenuated phosphorylation of the ERK1/2 MAP kinases. In summary, our sensor directly assesses the kinetics of CB1 activation in real-time and can be used to monitor CB1 structure and function.

Item Type:Articles
Keywords:Cannabinoid receptor, ERK1/2 MAP kinase, FRET sensors, G protein-coupled receptor, receptor activation.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Ward, Dr Richard
Authors: Liu, Y., Chen, L.-Y., Zeng, H., Ward, R., Wu, N., Ma, L., Mu, X., Li, Q.-L., Yang, Y., An, S., Guo, X.-X., Hao, Q., and Xu, T.-R.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
Journal Name:International Journal of Biochemistry and Cell Biology
Publisher:Elsevier
ISSN:1357-2725
ISSN (Online):1878-5875
Published Online:05 April 2018

University Staff: Request a correction | Enlighten Editors: Update this record